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Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

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Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#151

Post by DanBC »

panpanna wrote: post #145
DanBC wrote: post #140

Earlier quoted context omitted.

> A lot of fakes were distributed through reputable sources as originals. So you could for example build a medical device using expensive original components from digikey Medical device manufacturers would want both certificates of conformity and traceable parts. They'd want these if they built the product themself; they'd specify this if they got a sub-contract manufacturer. If the component supplier can't offer tra…

The problem is that these devices came from legitimate sources with the right paperwork.

I find it hard to believe that anyone got traceability information with these fake devices.

I can't understand how a component supplier would comingle their traceable stock.

EDIT: since this is getting downvotes.

A component supplier would destroy customer trust if they supplied fakes with traceability certificates. It would mean anyone building for aerospace or military or medical or mining or etc etc (all large, multibillion dollar industries) would have to avoid that supplier. So what's in it for the component supplier?

I accept the fakes are common. I accept people bought fakes from reputable suppliers. What I don't accept is that people bought fakes when they asked for traceable components. I don't accept that companies buyign direct from FTDI got fake components.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#152

Post by whatusername »

as-j wrote: post #6

This affects temperature sensors/parts bought from un-official distributors like ebay or AliExpress, not digikey, farnel, etc. Perhaps I've been too lucky in my career and practiced EE for work, but who would you ever go to ebay instead of digikey?? Digikey certainly has a premium, but their speciality is small numbers/cut tape/etc and they have a small order size which makes them ok for hobby work, and I've used the…

So I ordered a ds18b20 sensor last year from ebay. paid AUD $1.88 for it (including shipping). Digikey looks to be $7 plus $20 shipping (and I'm not certain if those are USD or AUD)

As someone who doesn't do this for work - I've never seen/heard of digikey or farnel before. Maybe if I was ordering enough to hit the $60 free shipping limit - but I don't think I've spent that on electrical bits in the last year.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#153

Post by andi999 »

lutorm wrote: post #90
bigiain wrote: post #73

Earlier quoted context omitted.

Same. I read through this thinking "What, my team sensor on the data logger for my coffee grinder might be more than half a degree out? You know what? I totally don't care, and wouldn't have spent an extra 50 cents to get that much accuracy..." I do have ethical qualms about supporting/funding "stolen IP", but then I've kinda got ethical qualms about the whole concept of IP anyway, and if you wanted to go hardline on…

If you don't need that accuracy, why would you use a DS18B20 in the first place. You can use a dirt cheap NTC.

Maybe you want to save on the A/D hardware?

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#154

Post by marcan_42 »

analog31 wrote: post #72
kregasaurusrex wrote: post #36

Trust in hardware supply chains when manufactring a PCB for a product can be quite fragile: when one component operates outside of spec, the entire device could be rendered useless. In the case of the DS18B20, the author states in the 'Warning' section that the primary way of determining counterfeit sensors is to check the ROM output compared to a known format. When counterfeit parts like this are added, it creates v…

If I recall correctly, FTDI took some well deserved heat, but quickly discontinued this practice.

The really sad thing is that the FTDI clones worked better than the original ones.

The original FT232R chips have a clocking bug that makes bitbang mode unusable for many applications, with no workaround (their errata sheet suggests a bullshit workaround of setting the clock speed to max, that is unusable in practice because USB can't keep up). It's supposedly fixed in a revision that I've never seen, and I believe they never manufactured it.

The clones... work perfectly fine: https://twitter.com/marcan42/status/695292366639378433

In fact, I reverse engineered FTDI's bricker, and it works by exploiting the fact that their own chips violate their own interface design by requiring EEPROM words to be written back to back - even word writes alone are staged and ignored without an odd word write. The clones honor the writes independently, like FTDI's other chips. Their bricker code only writes even EEPROM words and preimage attacks their own checksum algorithm (since the real checksum is at an odd word they can't touch) to make it work, so it has no effect on the real chips (which get sent the same commands). It's hilarious.

Don't buy FTDI. They're just bad.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#155

Post by robomartin »

kd5bjo wrote: post #148
robomartin wrote: post #143

Earlier quoted context omitted.

Read my comment about how there are at least two separable problems in this issue. Perhaps then my position will make sense to you. Continuing to argue through hypothetical examples is pointless, it's getting sillier and sillier and farther away from key issues. Counterfeit goods is not a victimless crime. It costs jobs. It costs progress. It costs entire industries. Don't blame the victim. Consumers just happen to b…

> I mean, what's FTDI supposed to do? I’m not saying that FTDI or a similar company should sit idly by, but the vigilante justice you’re advocating leads to bad places. We have customs enforcement to stop goods at the border and a court system to deal with internal disputes; use them.

> We have customs enforcement to stop goods at the border and a court system to deal with internal disputes

It's a joke, right? This system has allowed everything from fake hats to fake, well, everything, to come into the country undeterred. Amazon and eBay are full of the stuff. It's so brazen that they are not shipping fakes directly into the US through highly subsidized door-to-door shipping using the US Postal Service.

And you want them to police an obscure little chip out of millions that come through the gates? My friend, our system is powerless against the onslaught...and they know it. Sure, a few things get nabbed here and there. This is a rounding error at the scale and breath of what's going on.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#156

Post by user5994461 »

yjftsjthsd-h wrote: post #102
metaphor wrote: post #82

Earlier quoted context omitted.

> However simply repeating requests until sensor reports a valid value (!=+85C and !=-127C) works fine. You know you're dealing with counterfeits and you know they're unreliable, but you've somehow convinced yourself that despite all the uncovered variance sitting on the table, if you keep poking long enough until the component returns some non-edge-case value, then it "works fine". I must have hopped on the sanity t…

> You know you're dealing with counterfeits and you know they're unreliable, but you've somehow convinced yourself that despite all the uncovered variance sitting on the table, if you keep poking long enough until the component returns some non-edge-case value, then it "works fine". Yes? Because it usually does? If you test a bunch of fakes and they tend to be either basically accurate xor really inaccurate, and your…

Are these SMT components that have to be soldered for testing? Hardware is not as trivial as software to test and replace.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#157

Post by metaphor »

yjftsjthsd-h wrote: post #102
metaphor wrote: post #82

Earlier quoted context omitted.

> However simply repeating requests until sensor reports a valid value (!=+85C and !=-127C) works fine. You know you're dealing with counterfeits and you know they're unreliable, but you've somehow convinced yourself that despite all the uncovered variance sitting on the table, if you keep poking long enough until the component returns some non-edge-case value, then it "works fine". I must have hopped on the sanity t…

> You know you're dealing with counterfeits and you know they're unreliable, but you've somehow convinced yourself that despite all the uncovered variance sitting on the table, if you keep poking long enough until the component returns some non-edge-case value, then it "works fine". Yes? Because it usually does? If you test a bunch of fakes and they tend to be either basically accurate xor really inaccurate, and your…

"usually"..."basically"..."probably"...that's a lot of handwaving. Your usecase is both your prerogative and your folly to embrace; that's not the point.

I poke fun at the OP because his qualifier for "works fine" is an indeterminate definition of eventually establishing some semblance of compliant 1-wire communication with a counterfeit component without even so much as batting an eye to question the accuracy of the sensor measurement being read in, let alone:

  a) environmental constraints
  b) electrical constraints
  c) timing constraints
  d) system integration considerations
  e) counterfeit variance/unpredicability
No, this is not even remotely asymptotic to the implications of software unit testing. This is physical hardware which manifests real variance "vetted" by some half-baked functional "test" that completely ignores every parametric spec without discrimination. Without questioning implementation merits, your software unit tests operate on hash-replicable code...at the silicon level, such a luxury doesn't exist.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#158

Post by robomartin »

IAmEveryone wrote: post #149
robomartin wrote: post #124

Earlier quoted context omitted.

One bad example after another. Why is this so hard for folks to grasp. The proper example would be fake iPhones made in Switzerland sold in the US as through they were real iPhones. If that's the case, then, YES, Apple would be right to brick them with an update. Absolutely. I ask again: In what alternate reality would Apple be required to allow fake iPhones, look the other way and just let them be?

> I ask again: In what alternate reality In that alternative reality where, for example, mobile phone carriers are required to allow 911 calls even if your account is otherwise locked because you fraudulently paid with someone else's credit card.

I can play that game too. The fakes are so bad there is no telling if you are going to be able to reach 911 or, if you do, they don't report correct GPS coordinates. 9.2% of the people who call 911 never get through and 3.05% die.

Even NADCAR races have a limited number of laps for a reason. We can go around and around this silly pile of hypothetical cases and lose complete sight of the fact that the root cause of the problem is intellectual property theft at a massive scale and that this has serious consequences. The FTDI issue is but a rounding error in this massive global mess. Let's not blame the victim. That is not what a fair society does.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#159

Post by pugz »

robomartin wrote: post #121
fulafel wrote: post #113

Earlier quoted context omitted.

You are talking about compatibility but the FTDI case was a case of the company intentionally shipping malicious code used to brick the clones, no? Quote from article: "the latest driver bricks the fake chips, rendering them inoperable with any computer"

Well done. They have the absolute right to create drivers that only work with their products in order to assure quality, performance and function. Fault is at the feet of the clone makers and those who used clone chips, not the legitimate manufacturer. I am actually astounded by some of these responses. However, I do understand that they likely come from a lack of experience delivering hardware products at scale, and…

No one is disputing that "they have the absolute right to create drivers that only work with their products in order to assure quality, performance and function." - that's a given.

Would you say that they also have "the absolute right to create drivers that sabotage counterfeits of their products"?

That's a different argument. You could argue that they should have the right given that (elsewhere you have argued) their governments have abrogated their responsibility to protect their IP. And that would be an interesting and compelling argument. But it's entirely different to "[having] the absolute right to create drivers that only work with their products in order to assure quality, performance and function." - and it would be disingenuous to keep arguing that.

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